Underreamer.



J. M. DELMORE.

UNDERREAMEB..

4 APPLICATION lFILED AUG. 1, 1911. 1,031,628. Patented July 2,1912.

? d@ )gf/95% JOSEPH M. DELMORE, 0F LOS ANGELES, CALIFORNIA.

UNDERREAMER.

Specification of Letters Patent.

Application led August 1, 1911. Serial No. 641,783.

' cutters will expand to cut around a complete circle or a very largeproportion thereof. In its preferred form I utilize three cutters; butit will be seen that any number may be used.

The gist of the invention is contained in the construction which allowsthe use of three or more cutters. And one of the prime advantages of myunderreamer is its provision for three or more cutters; but the'construction which allows of this 1s of such 'simple and practicalnature that it may be used to advantage in a two cutter construction ifdesired.

Heretofore, so far as I am aware, most underreamers have been providedwith only two cutters and have been able to cut over only about half ofthe circle of the well hole. IVith my underreamer nearly the wholecircle is cut over at each stroke; thus insuring a uniformly cylindricalhole.

In the drawings I have shown a preferred form of my construction,illustrating an underreamer with three cutters.

In these drawings: Figure 1 is a longitudinal section showing myunderreamer in.

position for insertion in a well. Fig. 2 is a longitudinal sectionshowing the underreamer with its cutters expanded ready yfor drillingoperations. Fig. 3-is across section taken on lines 3 3 of Figs. 2 and5. Fig. 4 is a cross sectiontaken on line 4.-4 of Fig. 2. Fig. 5 is anenlargedfragmentary longitudinal section taken as indicated Fig. 3. Fig.6 is a longitudinal section taken on line 6-6 of Fig. 5. Fig. 7 is abottom view of the underreamer as shown in Fig.

In' thel drawings 10 designates a mandrel having a suit-able connectingmeans 11 on its a longitudinal bore 12 therein. This longitudinal bore12 is enlarged into a conical opening 13 of any suiti upper end andhavin able shape at the lower end of the mandrel. A longitudinal rod 14is secured in the mandrel at lts upper end, as at 15, and itslower endhas an enlargement 16 thereon. This enlargement 16 is typicall below thelower end of the mandrel and 1s held stationary from the stationary rod14. Mounted around rod 14 and sliding within the bore 12 Patented July2, 1912.

of the mandrel is a barrel 20. Rod 14carries a collar 21 upon which acompression spring 22 is supported, the upper end of this springpressing upwardly against a collar 23 in the upper end ofthe barrel 20,thus tending to raise the barrel to its uppermost position. The lowerportion lof the barrel 20 is reduced, as shown at 20a, and this reducedportion carries on its lower end an enlargement 25. The movement ofbarrel 20 is sufficient to move the enlarged portion 25 from theposition shown in Fig 1 to the position shown in Fig. 2. Enlargement 25provides a means for connecting the barrel 20 with the cut-ters of theunderreamer; and is typical of other methods of connection which may beused. l

Cutters 30 are preferably three in number and are each provided withupper portions 30a which t into the conical opening 13 in the lower endof the mandrel and which fit around the reduced portie-n 20al of barrel20.

This is perhaps best shown in Figs. 2 and 3.

In this posit-ion of the cutters vthe lower ends SObare expanded to theposit-ion shown in Fig. 2. IThe upper ends of the cutters bed solidlyagainst the mandrel and against the portion 20a of the barrel and t-hecutters are thereby held solidly in position. In this positioninwardly'projecting portions 30c of the cutters bear againstenlargement- 16, and the lower ends of the vcutters are thus solidlyheld in their expanded position. Shoulders 30d of the cutters rest'uponenlargement 25; and the cut-ters are thus supported by the spring 22which supports barrel 20. When the barrel 20 is lowered, as when theunderreamer is passing through the casing 50, the cutters are lowered tothe position shown in Fig. 1, so that the recesses 30e in each of thecutters directly above portions 30c will then be opposite enlargement 16and will allow the cutters to contract to the position shown in Fig. 1.When the underreamer is in this condition, both enlargements 16 and 25will v be surrounded by the recesses 80. The up A perl ends ofthefcutters do not then touch each other but hang comparatively looselyin the conical opening 13 and around the portion 20a of barrel 20.Immediately the underreamer passes out of the casing the spring 9.2raises `the barrel 20 and raises the cnt-ters, forcing their upper endsinto solid engagement with the mandrel and with the portion 20a ofbarrel 20 and forcing the portions 30c of the cutters into engagementwith enlargement 16. This causes, as before eX- plained, the positioningof the cutters as shown in Fig. 2; and it will be. seen thatin thisposition t-he cutters are solidly supported against inward transversethrust at their lower ends and against. longitudinal upward thrust.

Although the cutters are held within the mandrel by being connected withthe barrel.

20, I additionally provide for retaining them within the mandrel bymeans of the device shown in Figs. 3, 5 and G. This device is intendedto act as a safety appliance in case spring QQ-should break and allowthe barrel 20 to lower; or in case the rod-14 should break and otherwiseallow the barrel and the cutters to fall completely out of the mandrel.In each of the upper ends 30aL of the cutters 30.1 have provided a slotG0 which is wider at its lower end than at its upper end. Shoulders G1are thus `formed against which the enlarged end portion G2 of link 63may engage. Link 63 is placed in the position shownand has an enlargedupper end 64 which engages in a, slot 65 in barrel 9.0, this slot beingof such configuration as to afford shoulders 6G against which theenlarged portion (Se may bear. Slots 60 and enlarged portions G2allow'the cutters 30 their proper' vertical movement; but

should the cutters have a tendency to drop farther, the links 63 willprevent this.

From the foregoing it will be seen that my invention consists broadly inthe provision of certain mechanism whereby a multiple cutter underreamermay be constructed; and specifically in the combination of theconcentric vertically moving parts'which support andcontrol the actionof the cutters. It is to these parts that I wish to particularly directthe following claims; desiring to cover broadly the combinationsdescribed. For this purpose Ithe exact conformation Vof the severalparts is of n'o great importance; and particularly is this true of thecentral rod and its surrounding barrel.

The barrel may be 'considered broadly asa resiliently supported cuttersupporting member, while the main function 'of the rod is to expandl thecutters which engage its lower end. Although I have adopted and shown apractical form for the working combination of the rod, barrel andcutters, the exact designs described are not essential.

Other arrangements may be substituted for VV'those specifically andpreferably described without exceeding the scope of my invention.

Having described my invention, I claim: 1. In an underreamer comprisinga tubular body having an attaching end, said body having a bore with areduced upper portionv and an enlarged mouth portion, a rod, a barrelmounted upon the rod, said rod being secured in the reduced portion ofthe bore against movement,enlarged portions formed .at the lower ends ofthe rod and barrel, expansible means around t-he rod and within thebarrel for 'holding said enlarged portions normally separated and thebarrel in an upward position, and cutter' members having linkconnections with the barrel above the enlarged portions and havinginwardly projecting portions engageable with said enlarged portions.

2. An underreamer comprising a tubular `mandrel having an Venlargedconical opening at its lower end, a vertical rod secured to the mandrelatyits upper end and passing down through its interior, an enlargedportion on the lower end of the rod near thc enlarged conical opening, avertically. movable barrel on the rod and within the mandrel, an en-'larged portion on the lower end of the barrel above the enlargedportion on the rod, a coiled spring around the rod within the barrel andacting to raise the barrel, and cutters supported on the barrelenlargedportion and having portions engageable with the rod enlargedportion, the upper ends of the cut-ters fitting into the conical openingin the lower end of the mandrel..

3.' An underreamer comprising a hollow -mandrel having a conical openingat its lower end, a longitudinal rod allixed at its upper end to themandrel and extending through the mandrel to a point near its lower end,a barrel within the hollow mandrel and surrounding the rod, resilientmeans for supporting the barrel, cutters having upper ends adapted tofit within the conical lower opening of the mandrel andl having portionsengaging the lower end of the longitudinal rod, and connectingl meansbetween the cutters and the barrel.

4. An' underreamer, comprising a hollow mandrel having an upwardlytapering opening at its lower end, a' vertical rod secured at its upperend to the mandrel and projecting down through the tapering opening, abarrel slidable on said rod within the mandrel, resilient means to movethe barrel upwardly on t-he rod, and a set of cutters supported by thebarrel and having portions adapted to lit within the mandrel opening andportions adapted to engage the lower end of said rod'.

5. An underreamer, comprising a mandrel having an upwardly taperingopening at its lower end, a vertical rod secured at its upper end -to4the mandrel and projecting down In Witness that I claim the foregoing Ithrough said tapered opening, a. cutter suphave hereuntoisubscribed myname this 25 10 porting member slidable on th?) rod, resiliday of July1911.

ent means to su ort said mem er, and cutters supported lfiythe saidmember and hav- JOSEPH'M' DLLMORE' ing portions engaging Wit-hin saidtapered Witnesses:

opening and portions engaging the lower JAMES T. BARKELEW,

end of said rod. JAS. H. BALLAGH.

